/*-
 * Public platform independent Near Field Communication (NFC) library examples
 * 
 * Copyright (C) 2009, Roel Verdult
 * Copyright (C) 2010, Romuald Conty
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *  1) Redistributions of source code must retain the above copyright notice,
 *  this list of conditions and the following disclaimer. 
 *  2 )Redistributions in binary form must reproduce the above copyright
 *  notice, this list of conditions and the following disclaimer in the
 *  documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 * 
 * Note that this license only applies on the examples, NFC library itself is under LGPL
 *
 */

/* Emulates a tag which which have a "really" custom UID
 * 
 * NFC devices are able to emulate passive tags but manufacturers restrict the
 * customization of UID. With PN53x, UID is only 4-byte long and the first
 * byte of emulated UID is hard-wired to 0x08 which is the standard way to say
 * this is a random UID.  This example shows how to emulate a fully customized
 * UID by "manually" replying to anti-collision process sent by the initiator.
 */

#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <stdint.h>
#include <string.h>
#include <signal.h>

#include <host/nfc.h>

#include "nfc-utils.h"

#define MAX_FRAME_LEN 264

static byte_t abtRecv[MAX_FRAME_LEN];
static size_t szRecvBits;
static nfc_device_t *pnd;

/* ISO14443A Anti-Collision response */
byte_t abtAtqa[2] = { 0x04, 0x00 };
byte_t abtUidBcc[5] = { 0xDE, 0xAD, 0xBE, 0xEF, 0x62 };
byte_t abtSak[9] = { 0x08, 0xb6, 0xdd };

void intr_hdlr(void)
{
	if (pnd != NULL) {
		printf("\nAborting current command...\n");
		nfc_abort_command(pnd);
	}
}

void print_usage(char *argv[])
{
	printf("Usage: %s [OPTIONS] [UID]\n", argv[0]);
	printf("Options:\n");
	printf("\t-h\tHelp. Print this message.\n");
	printf("\t-q\tQuiet mode. Silent output: received and sent frames will not be shown (improves timing).\n");
	printf("\n");
	printf("\t[UID]\tUID to emulate, specified as 8 HEX digits (default is DEADBEEF).\n");
}

int main(int argc, char *argv[])
{
	nfc_target_t nt;
	nfc_iso14443a_info_t nai = {
		{ 0x04, 0x00 },
		0x20,
		4,
		{ 0x08, 0xad, 0xbe, 0xef },
		0,
	};
	byte_t *pbtTx = NULL;
	size_t szTxBits;
	bool quiet_output = false;
	int arg, i;
	
	/* Get commandline options */
	for (arg = 1; arg < argc; arg++) {
		if (0 == strcmp (argv[arg], "-h")) {
			print_usage (argv);
			exit(EXIT_SUCCESS);
		} else if (0 == strcmp (argv[arg], "-q")) {
			printf ("Quiet mode.\n");
			quiet_output = true;
		} else if ((arg == argc - 1) && (strlen (argv[arg]) == 8)) {        // See if UID was specified as HEX string
			byte_t  abtTmp[3] = { 0x00, 0x00, 0x00 };
			printf ("[+] Using UID: %s\n", argv[arg]);
			abtUidBcc[4] = 0x00;
			for (i = 0; i < 4; ++i) {
				memcpy (abtTmp, argv[arg] + i * 2, 2);
				abtUidBcc[i] = (byte_t) strtol ((char *) abtTmp, NULL, 16);
				abtUidBcc[4] ^= abtUidBcc[i];
			}
		} else {
			ERR ("%s is not supported option.", argv[arg]);
			print_usage (argv);
			exit(EXIT_FAILURE);
		}
	}
	
#ifdef WIN32
	signal(SIGINT, (void(__cdecl *)(int))intr_hdlr);
#else
	signal(SIGINT, (void(*)(void))intr_hdlr);
#endif
	
	/* Try to open the NFC device */
	pnd = nfc_connect(NULL);
	
	if (pnd == NULL) {
		printf("Unable to connect to NFC device\n");
		exit(EXIT_FAILURE);
	}
	
	printf("\n");
	printf("Connected to NFC device: %s\n", pnd->acName);
	printf("[+] Try to break out the auto-emulation, this requires a second NFC device!\n");
	printf("[+] To do this, please send any command after the anti-collision\n");
	printf("[+] For example, send a RATS command or use the \"nfc-anticol\" or \"nfc-list\" tool.\n");
	
	/* Note: We have to build a "fake" nfc_target_t in order to do
	 * exactly the same that was done before the new nfc_target_init()
	 * was introduced.
	 */
	nt.nm.nmt = NMT_ISO14443A;
	nt.nm.nbr = NBR_UNDEFINED;
	memcpy(&nt.nti.nai, &nai, sizeof (nai));

	if (!nfc_target_init(pnd, &nt, abtRecv, &szRecvBits)) {
		nfc_perror(pnd, "nfc_target_init");
		ERR("Could not come out of auto-emulation, no command was received");
		goto error;
	}
	printf("[+] Received initiator command: ");
	print_hex_bits(abtRecv, szRecvBits);
	printf("[+] Configuring communication\n");
	if (!nfc_configure(pnd, NDO_HANDLE_CRC, false) ||
	    !nfc_configure(pnd, NDO_HANDLE_PARITY, true)) {
		nfc_perror(pnd, "nfc_configure");
		exit(EXIT_FAILURE);
	}
	printf("[+] Done, the emulated tag is initialized with UID: %02X%02X%02X%02X\n\n", abtUidBcc[0], abtUidBcc[1],
	       abtUidBcc[2], abtUidBcc[3]);
	
	while (true) {
		/* Test if we received a frame */
		if (nfc_target_receive_bits(pnd, abtRecv, &szRecvBits, NULL)) {
			/* Prepare the command to send back for the
			 * anti-collision request
			 */
			switch (szRecvBits) {
			case 7:
				/* Request or Wakeup */
				pbtTx = abtAtqa;
				szTxBits = 16;
				/* New anti-collsion session started */
				if (!quiet_output)
					printf ("\n");
				break;
				
			case 16:
				/* Select All */
				pbtTx = abtUidBcc;
				szTxBits = 40;
				break;
				
			case 72:
				/* Select Tag */
				pbtTx = abtSak;
				szTxBits = 24;
				break;
				
			default:
				/* unknown length? */
				szTxBits = 0;
				break;
			}
			
			if (!quiet_output) {
				printf("R: ");
				print_hex_bits(abtRecv, szRecvBits);
			}
			/* Test if we know how to respond */
			if (szTxBits) {
				/* Send and print the command to the screen */
				if (!nfc_target_send_bits(pnd, pbtTx, szTxBits, NULL)) {
					nfc_perror(pnd, "nfc_target_send_bits");
					goto error;
				}
				if (!quiet_output) {
					printf("T: ");
					print_hex_bits(pbtTx, szTxBits);
				}
			}
		}
	}
	nfc_disconnect(pnd);
	exit(EXIT_SUCCESS);
	
error:
	nfc_disconnect(pnd);
	exit(EXIT_FAILURE);
}
